Several common cryptographic functions of PHP

In the development process of the website, we often need to encrypt some data (such as user password), this article mainly introduces several common cryptographic functions of PHP:

MD5 Encryption:

　　

String MD5 (string $str [, bool $raw _output = false])

1.MD5 () returns the hash value by default as a 32-character hexadecimal number, which accepts two parameters, the first is the string to encrypt, the second is a Boolean value of Raw_output, the default is False, and if set to TRUE,MD5 () returns the original 16 BITS binary Format Message summary

2.MD5 () is a one-way encryption, there is no reverse decryption algorithm, but still can be some common string through collection, enumeration, collision and other methods to crack

<?php $username = Jellybool '; $password = ' jellybool.com '; /* simply MD5 encrypt the string */echo MD5 ($ username); echo "echo MD5 ( $password); echo "/* more recommended is to encrypt important sensitive data multiple times to avoid being easily cracked */echo MD5 (MD5 ( $password)); /* above output: username:4f5436e5d72608fb647b691e8edcf42e password:7bf02cf0f4af6da4accbc73d2a175476 Password (two-time encryption): 864704bb35754f8cd0232cba6b91521b */

Crypt Encryption:

String crypt (String $str [, String $salt])

1.crypt () accepts two parameters, the first is a string that needs to be encrypted, the second is a salt value (which is the encryption interference value, if not provided, it is automatically generated by PHP); Returns the hashed string or a string less than 13 characters, which is to distinguish the salt value.

2.crypt () is one-way encryption, just like MD5.

<?php$password =' Jellybool.com ';Echo Crypt ($password);Output: $1$fe0.qr5. $WOhkI 4/5vpo7n7tnxhh5k/* The eight characters between the second $ and the third $ are generated by PHP and change once per refresh */echo "echo Crypt ( $password, " Jellybool "); //output: Je7fniu1knaes /* when we want to add a custom salt value, As the example of Jellybool is added as the second parameter directly, the top two bits exceeding two characters will be intercepted */echo "echo Crypt ( $password, $1$ Jellybool$ '); //output: $1$jellyboo$dxh7wf7sygrpwb6xbbgfh//* Crypt encryption function has a variety of salt value encryption support, the above example shows that the MD5 hash as the salt value, in this way the salt value in the form of $1$$, such as the example of the Jellybool plus the next two $ characters, beyond the eight-character will intercept the first eight, the total length of 12 bits; Crypt is this form by default. */echo "//crypt also has a variety of salt value encryption support, see the manual

SHA1 Encryption:

String SHA1 (String $str [, bool $raw _output = false]

1. Unlike MD5, the difference is that SHA1 () returns a hash value of 40 characters by default, passing in a parameter, the first is an encrypted string, the second is a Boolean value of Raw_output, the default is False, and if set to TRUE,SHA1 () returns the original 20 Bit RAW Format Message summary

2.SHA1 () is also a single-line encryption, no reverse decryption algorithm

<?php $my _intro="Jellybool"; Echo SHA1 ($my _intro); //output: C98885C04C1208FD4D0B1DADD3BD2A9FF4D042CA echo "//Of course, multiple cryptographic algorithms can be mixed using echo MD5 (SHA1 ($my _intro)); / /output: 94f25bf9214f88b1ef065a3f9b5d9874 //This method of double encryption can also improve the security of data

UrlEncode Encryption:

String UrlEncode (String $str)

1. A parameter, passing in the string to be encrypted (usually applied to the encryption of the URL),

2.urlencode is two-way encryption, can be encrypted with urldecode (strictly speaking, not true encryption)

3. Returns the string, in addition to-_, in this string. All non-alphanumeric characters are replaced with a percent sign (%) followed by a two-digit hexadecimal number, and a space is encoded as a plus (+).

<?php//urlencode () is typically used to hide plaintext data in a URL$my _urlencode="Jellybool.com?jellybool=true + 4-3%5= \&@!"; Echo UrlEncode ($my _urlencode);Output: jellybool.com%3fjellybool%3dtrue+%2b+4-3%255%3d+%5c%26+%40%21 Echo"$my _urldecode="Jellybool.com%3fjellybool%3dtrue+%2b+4-3%255%3d+%5c%26+%40%21 "; Echo UrlDecode ($my _urldecode);Output: Jellybool.com?jellybool=true +4-3%5= \&@! Restore theOutput echo of the $my _urlencode"$my _urldecode="Http://www.baidu.com/s?word=jellybool+%e8%a7%89%e7%b4%af%e4%b8%8d%e7%88%b1&tn=98236947_hao_pg&ie=utf-8 "; Echo UrlDecode ($my _urldecode);/* Output: http://www.baidu.com/s?word=jellybool feel tired not love &tn=98236947_hao_pg&ie=utf-8 Yes, this is in Baidu search Jellybool feel tired not love */* ========================================================================= solve the second classic problem ========================== =============================================== */$pre _url_encode= "jellybool.com?username=jellybool&password=jelly";//In actual development, we often have to construct this URL, which is no problem $url _decode = "jellybool.com?username=jelly&bool&password=jelly"; /* Note the difference between the above two variables: the first Username=jellybool, the second is username=jelly&bool in this case with $_get () to accept the problem, this can be solved by the following method */$ Username= "Jelly&bool"; $url _decode = "Jellybool.com?username=". UrlEncode ($username). " &password=jelly "; //This is a good solution to the problem/* summarize the Common urlencode () conversion characters? = =%3f = = = %3d% = %25 & = %26 \ = %5c + = %2b space + + */

Base64 encoded encryption:

String Base64_decode (String $encoded _data)

1.base64_encode () accepts a parameter, which is the data to be encoded (not the string here, because many times base64 is used to encode the image)

2.base64_encode () is bidirectional encrypted and can be decrypted with Base64_decode ()

<?php $my _intro=echo base64_encode ( $my _intro); echo "/* output: Smvsbhlcb29s5piv5lia5liq6lqr5p2q5pyj6auy5bqmloicqeiggoaciewuvew 6PIZOG7JOGOZMNINLJPRLUQYS5OCD5OOZ5PYJ5REX5BQM55QE5ZU95A625YWN5QOA5LQ Uqee6p+s8moi0qos8quwjjeerr0lu55s35bgm5lid * /echo base64_decode ( Smvsbhlcb29s5piv5lia5liq6lqr5p2q5pyj6auy5bqmloicqeigg Oaciewuvew6pizog7jogozmninljprluqys5ocd5ooz5pyj5rex5bqm55qe5zu95a6 25ywn5qoa5lquqee6p+ S8moi0qos8quwjjeerr0lu55s35bgm5lid '); /* output: Jellybool is a stature has height, shoulder width, chest muscle has thickness, thought has the depth of the national inspection-exempt five A-level high-quality pseudo front-end it male cock silk */

An example of a picture:

<?php/ * A picture of the application example */ $filename ="Https://worktile.com/img/index/index_video.png"; $data =file_get_contents ($filename); Echo Base64_encode ($data); /* Then you view the source code will get a large string of base64 strings, and then use Base64_decode () restore can get the picture * *

Several common cryptographic functions of PHP